For motor vehicles, such as cars, trucks and buses, the cost of fuel constitutes a significant expense for the vehicle's owner or user. For a hauling company, for example, the main expenditure items for the day-to-day operation of a vehicle consist, apart from the cost of acquisition of the vehicle and the vehicle's driver's salary, of costs of repair and maintenance and fuel for the propulsion of the vehicle. The fuel cost may impact the profitability of the hauling company to a great extent. Therefore, a number of different systems have been developed to reduce fuel consumption, such as efficient engines and fuel economical cruise controls.
FIG. 1 schematically shows a powertrain in a vehicle 100. The powertrain comprises one or several engines, for example comprising a combustion engine 101 and/or an electric motor 121, which in a customary manner, via an output shaft 102 on the one or several engines 101, 121, usually via one or several flywheels, is connected to at least one input shaft 109 in a gearbox 103, via a clutch 106. The clutch 106 may e.g. consist of an automatically controlled clutch, and may be controlled by the vehicle's control system via a control device 130. The control device 130 may also control the gearbox 103.
The gearbox 103 is here illustrated schematically as one device. However, the gearbox 103 may also physically consist of several cooperating gearboxes, for example a so-called range gearbox, a main gearbox and a split gearbox, arranged along the vehicle's powertrain. The gearbox may comprise a suitable number of gears. Today's gearboxes for heavy goods vehicles usually have twelve forward gears, two reverse gears and one neutral gear. If the gearbox 103 consists, physically, of several part-gearboxes as described above, these twelve propulsive gears are distributed with two gears in the range gearbox, three gears in the main gearbox and two gears in the split gearbox, jointly constituting twelve gear positions (2*3*2=12). The vehicle 100 further comprises drive shafts 104, 105, which are connected to the vehicle's driving wheels 110, 111, and which are operated by an output shaft 107 from the gearbox 103, via a shaft gear 108, such as e.g. a customary differential.
The vehicle 100 further comprises various different brake systems 170, such as a customary brake system, which may comprise brake plates with associated brake pads (not shown) arranged next to each wheel. The vehicle 100 may also comprise one or several additional/auxiliary brakes, such as exhaust brakes, retarders or decompression brakes (not displayed). The engine 101 may be controlled based on instructions from a cruise control, in order to maintain a constant actual vehicle speed and/or to vary the actual vehicle speed, for example in such a manner that an optimized fuel consumption is obtained within reasonable speed limits. The engine 101 may also be controlled by a driver of the vehicle.
The vehicle may also comprise a system 140 for monitoring the status and charging of one or several batteries, which may be used, for example, at the start of the combustion engine 101 with the help of a starting engine, at operation of the engine when the electric motor 121 is used to operate the vehicle, or for operation of one or several systems in the vehicle.
The vehicle may also comprise one or several systems using compressed air and/or hydraulic pressure, and therefore one or several compressors 150 may be comprised in the vehicle.
The vehicle may also comprise one or several devices 160 for temperature monitoring and/or temperature control. For example, the temperature of the one or several engines 101, 121, the temperatures for one catalyst in an exhaust purification device and/or the temperatures in a driver's cabin may be monitored and/or controlled with the use of the one or several devices 160 for temperature monitoring and/or temperature control.